In general, various applications for an information processing service are gradually upgraded (updated) with the passage of an operating period of time (see Patent Document 1). Service is generally stopped temporarily for work of updating such applications for an information processing service.
However, it is difficult to stop service temporarily to perform work of updating an application for a communication service, because a communication service such as mobile communication is a very socially important infrastructure service. If there is a fault in a new version immediately after the update, a recovery process of restoring to an old version is rapidly performed to minimize impact on users.